The present invention relates to an improvement in a loading device in an apparatus for recording a magnetooptical disc such as DVD-ROM, CD-ROM, CD for automotive vehicles or the like.
A conventional magnetooptical disc recording apparatus is designed in view of miniaturizing and making thinner.
In particular, a loading device for loading a magnetooptical disc for recording and reproducing information by using a laser beam to the magnetooptical disc and removing the used magnetooptical disc from above a driving unit to the outside is miniaturized and thinned.
As is well known, the loading device is adapted to insert the loaded magnetooptical disc between the driving unit and a clamper disposed movably up and down above the driving unit, to hold the magnetooptical disc on the driving unit and to lower the clamper, to clamp and hold the magnetooptical disc by driving unit and the clamper. An elevation mechanism for moving the clamper up and down is disposed on the lower surface of the clamper and a space into which the magnetooptical disc is to be inserted is formed between the elevation mechanism and the driving unit.
However, since the loading device is also to be designed to be thinned and miniaturized, the space into which the magnetooptical disc is to be inserted is also made small down to its limit. There is a high possibility that the elevation mechanism and the magnetooptical disc or the elevation mechanism and the clamper would be brought into contact with each other, causing a damage of the magnetooptical disc and a defect in the clamper.
Accordingly an object of the present invention is to provide a loading device in a magnetooptical disc recording apparatus that may keep a sufficiently wide space between an elevation mechanism and a driving unit when the magnetooptical disc is loaded or unloaded without positioning a holder lever constituting the elevation mechanism between a clamper and the driving unit, and may keep a space for avoiding contact between the holder lever and the magnetooptical disc when the clamper and the magnetooptical disc are attracted to the driving unit and rotated.
In order to attain the above objects, the present invention has the following technical means. Namely, according to the present invention there is provided a loading device in a magnetooptical disc recording apparatus for performing recording and reproducing information by using a laser beam to a magnetooptical disc;
the loading device comprising:
a chassis received and held in a receiving case of the magnetooptical disc recording apparatus, having a circular first opening portion substantially at a center and having an upper surface of a ceiling plate around the first opening portion as a support surface,
a driving unit having at a central portion an attracting portion to face an interior of the first opening portion and to support the magnetooptical disc and being drivingly rotated;
a disc-shaped clamper disposed at a predetermined gap immediately above the driving unit, having at a central portion of a lower surface an attracted portion and having a flange at a circumferential edge of an upper surface; and
an elevation mechanism disposed to be substantially flush with an outer circumference of the clamper so as to engage with and release the circumference of the flange of the clamper to move it up and down,
and being characterized by that the elevation mechanism has a plurality of retainer pins arranged at an equal interval on a circumference around the first opening portion on the ceiling plate of the chassis; an annular clamper base in which a second opening portion having substantially the same shape as that of the first opening portion is formed in the central portion and a plurality of arcuate elongate holes fitted and retained with the plurality of retainer pins are arranged at an equal interval on a circumference around the second opening portion and which is supported rotatably onto a support surface; a clamper base rotating means for drivingly rotating the clamper base along the plurality of arcuate elongate holes in a forward direction or a reverse direction by an inserting or a drawing action of the magnetooptical disc; and a plurality of flexible holder levers supported rotatably to a plurality of pivot shafts arranged at an equal interval around the second opening portion of the clamper base, provided at one end with retainer pieces projecting and slanting downwardly to face the inside and provided at the other end with cam grooves bent in a longitudinal direction for retaining the plurality of retainer pins, and
that a plurality of first cutaway portions are formed around a circumferential edge of the first opening portion of the chassis, a plurality of second cutaway portions are formed also in a circumferential edge of the second opening portion of the clamper base corresponding to the first cutaway portions and guide cams that move the ends of the holder levers upwardly by the rotation to the outside are formed to project in end portions at the circumferential direction sides of the respective first cutaway portions.
With such an arrangement, when the magnetooptical disc is loaded onto the driving unit, the elevation mechanism of the loading device rotates the retainer pieces at ends of the holder levers that are extended obliquely downwardly through the first cutaway portions and the second cutaway portions overlapped therewith, to move them outwardly by the forward rotation of the clamper base and by the guidance of the cam grooves. The clamper that has been released away from the retainer pieces is lowered and attracted onto the driving unit for supporting the magnetooptical disc. The ends of the retainer levers released away from the clamper ride on the guide cams to be kept in a standby condition to thereby keep a sufficiently wide space at the time of the rotation of the magnetooptical disc.
Also, when the magnetooptical disc is inserted or removed, the ends of the holder levers are rotated to move inwardly by the reverse rotation of the clamper base so that the retainer pieces slanted downwardly are retained at the lower surface of the flange of the clamper, and the retainer pieces at the ends of the holder levers are swung upwardly on, as fulcrums, the end portions of the circumferential direction sides of the first cutaway portion moving in the same direction by the further reverse rotation of the clamper base. The above-described clamper is separated away from the drive unit to be brought into the standby condition in the upper position to thereby keep a sufficiently wide space between the elevation mechanism and the driving unit.
Accordingly, the elevation mechanism and a plurality of holder levers constituting the elevation mechanism are disposed removably in a radially outward direction to be substantially flush with the clamper. The vertical motion and the opening and closing operation in the radial direction are given to the holder levers in cooperation with the rotation of the clamper base. As a result, when the magnetooptical disc is loaded or unloaded, the clamper is moved upwardly by the engagement with the holder levers. When the magnetooptical disc is rotated, the holder levers are separated from the surface of the magnetooptical disc through the guide cams while the holder levers being separated away to the outside of the clamper. It is therefore possible to keep a sufficiently wide space between the elevation mechanism and the driving unit and to realize the thinning of the loading apparatus.